diff options
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/Makefile.lib | 28 | ||||
| -rw-r--r-- | scripts/xz_wrap.sh | 23 |
2 files changed, 51 insertions, 0 deletions
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 396da16aabf..1c702ca8aac 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -262,6 +262,34 @@ cmd_lzo = (cat $(filter-out FORCE,$^) | \ lzop -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \ (rm -f $@ ; false) +# XZ +# --------------------------------------------------------------------------- +# Use xzkern to compress the kernel image and xzmisc to compress other things. +# +# xzkern uses a big LZMA2 dictionary since it doesn't increase memory usage +# of the kernel decompressor. A BCJ filter is used if it is available for +# the target architecture. xzkern also appends uncompressed size of the data +# using size_append. The .xz format has the size information available at +# the end of the file too, but it's in more complex format and it's good to +# avoid changing the part of the boot code that reads the uncompressed size. +# Note that the bytes added by size_append will make the xz tool think that +# the file is corrupt. This is expected. +# +# xzmisc doesn't use size_append, so it can be used to create normal .xz +# files. xzmisc uses smaller LZMA2 dictionary than xzkern, because a very +# big dictionary would increase the memory usage too much in the multi-call +# decompression mode. A BCJ filter isn't used either. +quiet_cmd_xzkern = XZKERN $@ +cmd_xzkern = (cat $(filter-out FORCE,$^) | \ + sh $(srctree)/scripts/xz_wrap.sh && \ + $(call size_append, $(filter-out FORCE,$^))) > $@ || \ + (rm -f $@ ; false) + +quiet_cmd_xzmisc = XZMISC $@ +cmd_xzmisc = (cat $(filter-out FORCE,$^) | \ + xz --check=crc32 --lzma2=dict=1MiB) > $@ || \ + (rm -f $@ ; false) + # misc stuff # --------------------------------------------------------------------------- quote:=" diff --git a/scripts/xz_wrap.sh b/scripts/xz_wrap.sh new file mode 100644 index 00000000000..17a5798c29d --- /dev/null +++ b/scripts/xz_wrap.sh @@ -0,0 +1,23 @@ +#!/bin/sh +# +# This is a wrapper for xz to compress the kernel image using appropriate +# compression options depending on the architecture. +# +# Author: Lasse Collin <lasse.collin@tukaani.org> +# +# This file has been put into the public domain. +# You can do whatever you want with this file. +# + +BCJ= +LZMA2OPTS= + +case $ARCH in + x86|x86_64) BCJ=--x86 ;; + powerpc) BCJ=--powerpc ;; + ia64) BCJ=--ia64; LZMA2OPTS=pb=4 ;; + arm) BCJ=--arm ;; + sparc) BCJ=--sparc ;; +esac + +exec xz --check=crc32 $BCJ --lzma2=$LZMA2OPTS,dict=32MiB |